pythoningLearning
diff --git a/‎opc/package.py‎
Lines changed: 17 additions & 0 deletions b/‎opc/package.py‎
Lines changed: 17 additions & 0 deletions
diff --git a/‎tests/test_package.py‎
Lines changed: 15 additions & 0 deletions b/‎tests/test_package.py‎
Lines changed: 15 additions & 0 deletions
@@ -107,12 +107,21 @@ def __new__(cls, partname, content_type, blob):
         return Part(partname, content_type, blob)
 
 
+class _Relationship(object):
+    """
+    Value object for relationship to part.
+    """
+    def __init__(self, rId, reltype, target, baseURI, external=False):
+        super(_Relationship, self).__init__()
+
+
 class RelationshipCollection(object):
     """
     Collection object for |_Relationship| instances, having list semantics.
     """
     def __init__(self, baseURI):
         super(RelationshipCollection, self).__init__()
+        self._baseURI = baseURI
         self._rels = []
 
     def __getitem__(self, idx):
@@ -123,6 +132,14 @@ def __len__(self):
         """Implements len() built-in on this object"""
         return self._rels.__len__()
 
+    def add_relationship(self, reltype, target, rId, external=False):
+        """
+        Return a newly added |_Relationship| instance.
+        """
+        rel = _Relationship(rId, reltype, target, self._baseURI, external)
+        self._rels.append(rel)
+        return rel
+
 
 class Unmarshaller(object):
     """
 
@@ -111,6 +111,10 @@ def it_constructs_a_part_instance(self, Part_):
 
 class DescribeRelationshipCollection(object):
 
+    @pytest.fixture
+    def _Relationship_(self, request):
+        return class_mock('opc.package._Relationship', request)
+
     def it_has_a_len(self):
         rels = RelationshipCollection(None)
         assert len(rels) == 0
@@ -125,6 +129,17 @@ def it_supports_indexed_access(self):
         except IndexError:
             pass
 
+    def it_can_add_a_relationship(self, _Relationship_):
+        baseURI, rId, reltype, target, external = (
+            'baseURI', 'rId9', 'reltype', 'target', False
+        )
+        rels = RelationshipCollection(baseURI)
+        rel = rels.add_relationship(reltype, target, rId, external)
+        _Relationship_.assert_called_once_with(rId, reltype, target, baseURI,
+                                               external)
+        assert rels[0] == rel
+        assert rel == _Relationship_.return_value
+
 
 class DescribeUnmarshaller(object):